name: frappe-core-logging description: > Use when implementing logging, error tracking, or monitoring in Frappe v14-v16. Covers frappe.logger() for file-based logging, frappe.log_error() for Error Log DocType entries, request logging, Sentry integration, and production logging patterns. Prevents common mistakes with print(), swapped log_error arguments, and sensitive data. Keywords: frappe.logger, log_error, Error Log, logging, Sentry,, where are the logs, how to log errors, error tracking, print not showing, production logs. monitor, request logging, error tracking, debug, production. license: MIT compatibility: "Claude Code, Claude.ai Projects, Claude API. Frappe v14-v16." metadata: author: OpenAEC-Foundation version: "3.0"

Frappe Logging & Error Tracking

Three Logging Mechanisms

Decision Tree

Need to log something?
│
├─ Application logging (info, debug, warnings)?
│  └─ frappe.logger("my_module").info("message")
│     → Writes to sites/{site}/logs/my_module.log
│
├─ Error that admins should see in Desk UI?
│  └─ frappe.log_error(title="Short desc", message=traceback)
│     → Creates Error Log document (queryable, auto-cleanup)
│
├─ Quick debug during development?
│  └─ frappe.errprint(variable) — shows in console
│     → NEVER leave in production code
│
├─ Track all HTTP requests?
│  └─ Set enable_frappe_logger: true in site_config.json
│     → Logs to frappe.web.log
│
├─ Performance monitoring?
│  └─ Set monitor: true in site_config.json
│     → Logs to monitor.json.log (JSON, per-request metrics)
│
└─ External error tracking (Sentry)?
   └─ Set FRAPPE_SENTRY_DSN environment variable
      → Auto-captures unhandled exceptions

Quick Reference: frappe.logger()

# Get a logger for your module (ALWAYS specify module name)
logger = frappe.logger("my_app")

# Standard Python logging levels
logger.debug("Detailed diagnostic info")
logger.info("Normal operations: processed 50 records")
logger.warning("Something unexpected but recoverable")
logger.error("Operation failed", exc_info=True)
logger.critical("System-level failure")

# Full signature
frappe.logger(
    module=None,          # Logger name + log filename
    with_more_info=False, # Auto-log request form_dict
    allow_site=True,      # Log under site's logs/ directory
    filter=None,          # Custom logging.Filter
    max_size=100_000,     # Max bytes per log file (100KB default)
    file_count=20         # Rotated files retained (20 default)
)

Log location: sites/{site}/logs/{module}.log Rotation: RotatingFileHandler — 100KB per file, 20 backups (~2MB total per logger)

Default Log Levels

# Change level dynamically
frappe.utils.logger.set_log_level("DEBUG")

Quick Reference: frappe.log_error()

# ALWAYS use keyword arguments (title/message can swap otherwise)
frappe.log_error(
    title="Payment gateway timeout",          # Short description (140 chars max)
    message=frappe.get_traceback(),            # Full error details
    reference_doctype="Payment Entry",        # Related DocType
    reference_name="PE-00001"                 # Related document
)

# Minimal — auto-captures current traceback
try:
    risky_operation()
except Exception:
    frappe.log_error(title="Operation failed")

Error Log cleanup: Auto-deletes after 30 days. Manual: frappe.whitelist: clear_error_logs()

Auto-Captured Exceptions

Unhandled exceptions (HTTP 500+) are automatically logged to Error Log.

Excluded from auto-capture:

• frappe.AuthenticationError
• frappe.CSRFTokenError
• frappe.SecurityException
• frappe.InReadOnlyMode

Production Configuration

site_config.json Keys

Environment Variables

Production Log Files

Anti-Patterns

Version Differences

Reference Files

• Logger API & Patterns — frappe.logger() advanced usage
• Error Tracking — Error Log, Sentry, monitoring